You don't have to be an arborist or an 8-year-old to go out and climb a tree. Recreational tree climbers come in all forms -- you just need some instruction, the right gear and a minimal fear of heights.

Before people go out on a hiking or climbing expedition, they typically prefer to know what's in store for them. How difficult will a climb be? Will it be relatively easy, or are there many obstacles along the way? Climbing grades attempt to answer these questions.